FERISrS— SPHENOPTEEIDE.E— SPHENOPTEKIS. 43 



SPHENOPTEKIS MISSOUKIENSIS 11. sp. 



PI. XIV, Figs. 1, 2. 



Primary (f) pinnse linear or linear-lanceolate, contracted at the base, 

 with bi-oad, very finely lineate rachis; pinnpe of the next order alternate, 

 open, nearly at a right angle to thp rachis in the lower part of the superior 

 pinna, becoming more oblique above, oblong-lanceolate or oval-lanceolate, 

 slightly contracted at the base, tapering rapidly in the upper part to a 

 short, acute point, straight or slightly flexuous, close, nearly touching or 

 overlapping a little, slightly dense, the rachis slender, slightly sinuate, 

 appearing on the lower side as a raised strand, with a narrow border; 

 ultimate pinnse very open, the lower ones nearly at a right angle to the 

 rachis, alternate, rather close, touching or slightly overlapping in the lower 

 portion of the frond, deltoid-oblong, obtuse or obtusely rounded at the apex, 

 broadest at the decurrent base, the lowest inferior one heteromorphous, the 

 uppermost succeeded by pinnatifid and simple pinnules ; pinnules alternate, 

 oblique, the angle of their origin averaging about 45°, short and broad, 

 cur\nng outward, close, nearly touching or sometimes overlapping, cuneate, 

 with round or round-truncate apex when small, or becoming obovate and 

 ovate or obovate-deltoid in the pinnatifid stage, ordinarily showing a marked 

 tendency toward a broadly cuneate form, with the apex cut by a shallow 

 sinus into 2 broad, rounded teeth or lobes, which are afterwards more 

 deeply separated, while others are formed from the upper division, so that 

 the pinnule is cut into about 8 or 9 short, broad, obtuse lobes before the 

 lower ones develop the cuneate, shallowly bifid form so common in the 

 plant; lamina not very thick, very minutel}^ striated in the direction of 

 the nervation, apparently by the presence of extremely small appressed 

 hairs; nervation fine, not very distinct, though slightly in relief on the 

 dorsal surface; primary nerve more or less distinctly decm-rent, forking low, 

 at a moderate angle, to furnish a single nervil for each lobe. 



The general aspect of this beautiful and graceful plant can be inferred 

 from the photograph, PL XIV, Fig. 1, prepared from the largest specimen 

 found in the collection. As noted in the description, the conspicuous char- 

 acter of the pinnule is the outward-curved, close, cuneate, more or less 

 bifid form, which after the development of other lobes is quickly reproduced 



